An aircraft wing is specifically designed to provide the necessary lift to carry the weight of the aircraft at desired speeds and/or altitudes. At high cruising speeds, the required airfoil area is significantly less than that required at slow landing speeds. For this reason, it is common for an aircraft wing to include a leading edge flap (often called a Kreuger flap) which moves between a stowed position, for high cruising speeds, and a deployed position for slow landing speeds. In the stowed position, the leading edge flap lies flush with, or forms a portion of, the lower surface of the wing. In the deployed position, the flap is pivoted outwardly to form a virtual extension of the convex upper surface of the wing so as to increase airfoil area.
It is important that the leading edge flap deploy at the appropriate time during flight, even in cold climate conditions where icing is inevitable. If ice-build up occurs over a portion of the flap (such as a fore portion, which can be the most ice-susceptible portion), it can prevent proper deployment of the flap. Moreover, the flap is often constructed from a thin composite structure, whereby such ice buildup could result in destruction of the flap during an attempted deployment.